Moving parts of a sound transducer, for example a loudspeaker and/or a receiver, include a membrane/voice-coil assembly which, in the case of a loudspeaker, is driven by an amplifier to produce sound based on an input signal and, in the case of a receiver has output voltage and/or current amplified by an amplifier. Excess amounts of voice coil and/or membrane excursion can be limited by a damping factor of the amplifier during operation, which generally has low impedance relative to the voice coil. While the amplifier is in a standby state and/or disabled state, the output impedance of the amplifier becomes high. This is problematic, and can become a serious concern, when the sound transducer is dropped on a hard floor and/or exposed to high acceleration of a force as, in this configuration, the membrane/voice-coil assembly is free to move. Hence, an excess amount of the voice coil excursion can result which, in a worst case scenario, results in the membrane/voice-coil assembly being damaged permanently.